Brilliant Energy has become the 10th supplier to cease trading in the past year.
The utility firm - which supplied gas and electricity to 17,000 households - was based in Gosforth and offered a "straightforward" service at a "fair and stable" price.
As with the other suppliers which have ceased trading in recent months, Ofgem will now appoint a “supplier of last resort” to take over Brilliant Energy’s customer accounts.
Philippa Pickford, Ofgem's director for future retail markets, said: "Our message to energy customers with Brilliant Energy is there is no need to worry, as under our safety net we will make sure your energy supplies are secure and your credit balance is protected."
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She said that customers should not switch for the time being. "We will update you when we have chosen a new supplier, who will then get in touch about your new tariff," she said.
"We have seen a number of supplier failures over the last year and our safety net procedures are working as they should to protect customers."
Peter Earl, head of energy at comparethemarket.com said that smaller firms were struggling with a spike in wholesale energy prices.
He said: “As the energy market becomes increasingly competitive, many customers have voted with their feet and switched to new providers, but the demise of yet another energy company may dent people’s confidence in backing challenger energy brands.
“With a quarter of all customers now supplied by small and medium sized suppliers, it is vital that Ofgem’s review into testing new suppliers ensures that firms are stress tested adequately.”